Phytochemical analysis and immunomodulatory activities in vitro and in vivo of Aframomum melegueta K Schum seed extracts.

Aframomum melegueta K Schum (A. melegueta), an herbaceous plant renowned for its medicinal seeds, was investigated for its potential immunomodulatory effects in vitro and in vivo using ethanolic and methanolic extracts. The immunomodulatory effect was evaluated by measuring antibody titers using the agglutination technique, while anti-inflammatory activity was assessed in a carrageenan-induced mouse paw edema model. In vitro immunomodulatory activity was measured by lysozyme release from neutrophils. Additionally, white blood cell counts were analyzed post-extracts treatment. The MTT assay was employed to determine cytotoxicity, and the biochemical parameters of liver toxicity were evaluated. Remarkably, both extracts exhibited a dose-dependent reduction in paw edema (p < 0.001), with the most significant reduction observed at 1 g/kg (78.13 and 74.27% for ethanolic and methanolic extracts, respectively). Neutrophil degranulation was significantly inhibited in a dose-dependent manner (p < 0.003), reaching maximal inhibition at 100 µg/mg (60.78 and 39.7% for ethanolic and methanolic extracts, respectively). In comparison to the control group, both antibody production and white blood cell counts were reduced. Neither of the extracts showcased any cytotoxicity or toxicity. These findings suggest that A. melegueta extracts exhibit immunosuppressive and anti-inflammatory activities due to the presence of various biomolecules.

Antitumoral activity of Caralluma europaea on colorectal and prostate cancer cell lines.

Caralluma europaea is a medicinal plant used in Moroccan popular medicine, which has been employed as a remedy attributed to its anti-inflammatory, antipyretic, antinociceptive, antidiabetic, neuroprotective, and antiparasitic properties. The aim of the present study was to investigate the antitumor activity of both the methanolic and aqueous extract of C. europaea. The effects of increasing concentrations of aqueous and methanolic extracts on human colorectal cancer HT-29 and HCT116 cell lines and human prostate cancer PC3 and DU145 cell lines were examined on cell proliferation using MTT assay and cell cycle analysis. The induction of apoptosis was also assessed by determining protein expression of caspase-3 and poly-ADP-ribose polymerase (PARP) cleavage by western blot. The methanolic extract of C. europaea exerted significant antiproliferative effects on HT-29 (IC50 values 73 µg/ml), HCT116 (IC50 values 67 µg/ml), PC3 (IC50 values 63 µg/ml) and DU145 cells (IC50 values 65 µg/ml) after 48 hr treatment. Further, incubation with methanolic extract of C. europaea induced cell cycle arrest in G1 phase and an apoptotic process for all treated cell lines. In conclusion, the present results suggest that C. europaea, exhibited that these natural compounds are significant apoptosis inducers which may have considerable potential for development of effective natural product anticancer agents.

Sensitization of human neutrophil defense activities through activation of platelet-activating factor receptors by ginkgolide B, a bioactive component of the Ginkgo biloba extract EGB 761.

Ginkgolide B (GKB, BN 52021) was described as a platelet-activating factor (Paf) receptor antagonist. However, it is not known whether all GKB biological effects are mediated through Paf receptor antagonism only. To gain insight into the drug mode of action, we investigated here the effects of GKB per se on functional and signaling activities in human polymorphonuclear leukocytes (PMN). Treatment of PMN with GKB (0.5-12 microM) stimulates a rapid and weak production of reactive oxygen species determined by chemiluminescence. ROS production required the activation of protein kinase C (PKC), tyrosine kinases and p38 mitogen-activated protein kinase as indicated by inhibitory effects of, respectively, GF 109203X (IC(50) of 0.5 microM), genistein (IC(50) of 0.5 microM) and SB 203580 (IC(50) of 0.2 microM) or SB 202190 (IC(50) of 1.1 microM). GKB stimulated a Pertussis toxin-sensitive PLD activity assessed by the formation of tritiated phosphatidic acid and choline. By contrast, GKB did prevent the Paf-mediated PLD activity and CL response (IC(50) of 2 microM). Interestingly, both GKB and Paf-induced CL response were prevented by selective Paf antagonists such as CV 6209 or WEB 2086 indicating that GKB may directly activate Paf receptors. Finally, GKB potentiated the CL response induced by fMet-Leu-Phe and zymosan. These results show that GKB is the first partial agonist of the Paf receptor described so far capable of priming the polymorphonuclear leukocyte function.